CollationElementIterator class is used as an iterator
to walk through each character of an international string. Use the iterator
to return the ordering priority of the positioned character. The ordering
priority of a character, which we refer to as a key, defines how a character
is collated in the given collation object.
For example, consider the following in Spanish:
"ca" -> the first key is key('c') and second key is key('a').
"cha" -> the first key is key('ch') and second key is key('a').
And in German,
"b"-> the first key is key('a'), the second key is key('e'), and
the third key is key('b').
The key of a character is an integer composed of primary order(short),
secondary order(byte), and tertiary order(byte). Java strictly defines
the size and signedness of its primitive data types. Therefore, the static
functions primaryOrder, secondaryOrder, and
tertiaryOrder return int, short,
and short respectively to ensure the correctness of the key
value.
Example of the iterator usage,
String testString = "This is a test"; RuleBasedCollator ruleBasedCollator = (RuleBasedCollator)Collator.getInstance(); CollationElementIterator collationElementIterator = ruleBasedCollator.getCollationElementIterator(testString); int primaryOrder = CollationElementIterator.primaryOrder(collationElementIterator.next());
CollationElementIterator.next returns the collation order
of the next character. A collation order consists of primary order,
secondary order and tertiary order. The data type of the collation
order is int. The first 16 bits of a collation order
is its primary order; the next 8 bits is the secondary order and the
last 8 bits is the tertiary order.
| Field Summary | |
|---|---|
| static final int |
Null order which indicates the end of string is reached by the cursor. |
| Method Summary | |
|---|---|
| int |
Return the maximum length of any expansion sequences that end with the specified comparison order. |
| int |
Returns the character offset in the original text corresponding to the next collation element. |
| int |
Get the next collation element in the string. |
| int |
Get the previous collation element in the string. |
| static final int |
Return the primary component of a collation element. |
| void |
Resets the cursor to the beginning of the string. |
| static final short |
Return the secondary component of a collation element. |
| void |
Sets the iterator to point to the collation element corresponding to the specified character (the parameter is a CHARACTER offset in the original string, not an offset into its corresponding sequence of collation elements). |
| void |
Set a new string over which to iterate. |
| void |
Set a new string over which to iterate. |
| static final short |
Return the tertiary component of a collation element. |
| Methods inherited from java.langObject |
|---|
public static final
int
NULLORDER
public
int
getMaxExpansion
(
int
order
)
public
int
getOffset
(
)
public
int
next
(
)
This iterator iterates over a sequence of collation elements that were built from the string. Because there isn't necessarily a one-to-one mapping from characters to collation elements, this doesn't mean the same thing as "return the collation element [or ordering priority] of the next character in the string".
This function returns the collation element that the iterator is currently pointing to and then updates the internal pointer to point to the next element. previous() updates the pointer first and then returns the element. This means that when you change direction while iterating (i.e., call next() and then call previous(), or call previous() and then call next()), you'll get back the same element twice.
public
int
previous
(
)
This iterator iterates over a sequence of collation elements that were built from the string. Because there isn't necessarily a one-to-one mapping from characters to collation elements, this doesn't mean the same thing as "return the collation element [or ordering priority] of the previous character in the string".
This function updates the iterator's internal pointer to point to the collation element preceding the one it's currently pointing to and then returns that element, while next() returns the current element and then updates the pointer. This means that when you change direction while iterating (i.e., call next() and then call previous(), or call previous() and then call next()), you'll get back the same element twice.
public static final
int
primaryOrder
(
int
order
)
public
void
reset
(
)
public static final
short
secondaryOrder
(
int
order
)
public
void
setOffset
(
int
newOffset
)
public static final
short
tertiaryOrder
(
int
order
)
